1 files changed, 130 insertions, 43 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 609d53f7a915..3c72a05dc326 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -50,6 +50,12 @@
 #define STATE_PENDING   1
 #define STATE_READY     2
 
+struct posix_msg_tree_node {
+        struct rb_node          rb_node;
+        struct list_head        msg_list;
+        int                     priority;
+};
+
 struct ext_wait_queue {         /* queue of sleeping tasks */
         struct task_struct *task;
         struct list_head list;
@@ -62,7 +68,7 @@ struct mqueue_inode_info {
         struct inode vfs_inode;
         wait_queue_head_t wait_q;
 
-        struct msg_msg **messages;
+        struct rb_root msg_tree;
         struct mq_attr attr;
 
         struct sigevent notify;
@@ -110,6 +116,90 @@ static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
         return ns;
 }
 
+/* Auxiliary functions to manipulate messages' list */
+static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
+{
+        struct rb_node **p, *parent = NULL;
+        struct posix_msg_tree_node *leaf;
+
+        p = &info->msg_tree.rb_node;
+        while (*p) {
+                parent = *p;
+                leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
+
+                if (likely(leaf->priority == msg->m_type))
+                        goto insert_msg;
+                else if (msg->m_type < leaf->priority)
+                        p = &(*p)->rb_left;
+                else
+                        p = &(*p)->rb_right;
+        }
+        leaf = kzalloc(sizeof(*leaf), GFP_ATOMIC);
+        if (!leaf)
+                return -ENOMEM;
+        rb_init_node(&leaf->rb_node);
+        INIT_LIST_HEAD(&leaf->msg_list);
+        leaf->priority = msg->m_type;
+        rb_link_node(&leaf->rb_node, parent, p);
+        rb_insert_color(&leaf->rb_node, &info->msg_tree);
+        info->qsize += sizeof(struct posix_msg_tree_node);
+insert_msg:
+        info->attr.mq_curmsgs++;
+        info->qsize += msg->m_ts;
+        list_add_tail(&msg->m_list, &leaf->msg_list);
+        return 0;
+}
+
+static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
+{
+        struct rb_node **p, *parent = NULL;
+        struct posix_msg_tree_node *leaf;
+        struct msg_msg *msg;
+
+try_again:
+        p = &info->msg_tree.rb_node;
+        while (*p) {
+                parent = *p;
+                /*
+                 * During insert, low priorities go to the left and high to the
+                 * right.  On receive, we want the highest priorities first, so
+                 * walk all the way to the right.
+                 */
+                p = &(*p)->rb_right;
+        }
+        if (!parent) {
+                if (info->attr.mq_curmsgs) {
+                        pr_warn_once("Inconsistency in POSIX message queue, "
+                                     "no tree element, but supposedly messages "
+                                     "should exist!\n");
+                        info->attr.mq_curmsgs = 0;
+                }
+                return NULL;
+        }
+        leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
+        if (list_empty(&leaf->msg_list)) {
+                pr_warn_once("Inconsistency in POSIX message queue, "
+                             "empty leaf node but we haven't implemented "
+                             "lazy leaf delete!\n");
+                rb_erase(&leaf->rb_node, &info->msg_tree);
+                info->qsize -= sizeof(struct posix_msg_tree_node);
+                kfree(leaf);
+                goto try_again;
+        } else {
+                msg = list_first_entry(&leaf->msg_list,
+                                       struct msg_msg, m_list);
+                list_del(&msg->m_list);
+                if (list_empty(&leaf->msg_list)) {
+                        rb_erase(&leaf->rb_node, &info->msg_tree);
+                        info->qsize -= sizeof(struct posix_msg_tree_node);
+                        kfree(leaf);
+                }
+        }
+        info->attr.mq_curmsgs--;
+        info->qsize -= msg->m_ts;
+        return msg;
+}
+
 static struct inode *mqueue_get_inode(struct super_block *sb,
                 struct ipc_namespace *ipc_ns, umode_t mode,
                 struct mq_attr *attr)
@@ -130,7 +220,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 
         if (S_ISREG(mode)) {
                 struct mqueue_inode_info *info;
-                unsigned long mq_bytes, mq_msg_tblsz;
+                unsigned long mq_bytes, mq_treesize;
 
                 inode->i_fop = &mqueue_file_operations;
                 inode->i_size = FILENT_SIZE;
@@ -144,6 +234,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
                 info->notify_user_ns = NULL;
                 info->qsize = 0;
                 info->user = NULL;      /* set when all is ok */
+                info->msg_tree = RB_ROOT;
                 memset(&info->attr, 0, sizeof(info->attr));
                 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
                                            ipc_ns->mq_msg_default);
@@ -153,16 +244,25 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
                         info->attr.mq_maxmsg = attr->mq_maxmsg;
                         info->attr.mq_msgsize = attr->mq_msgsize;
                 }
-                mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
-                if (mq_msg_tblsz > PAGE_SIZE)
-                        info->messages = vmalloc(mq_msg_tblsz);
-                else
-                        info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
-                if (!info->messages)
-                        goto out_inode;
+                /*
+                 * We used to allocate a static array of pointers and account
+                 * the size of that array as well as one msg_msg struct per
+                 * possible message into the queue size. That's no longer
+                 * accurate as the queue is now an rbtree and will grow and
+                 * shrink depending on usage patterns.  We can, however, still
+                 * account one msg_msg struct per message, but the nodes are
+                 * allocated depending on priority usage, and most programs
+                 * only use one, or a handful, of priorities.  However, since
+                 * this is pinned memory, we need to assume worst case, so
+                 * that means the min(mq_maxmsg, max_priorities) * struct
+                 * posix_msg_tree_node.
+                 */
+                mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
+                        min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
+                        sizeof(struct posix_msg_tree_node);
 
-                mq_bytes = (mq_msg_tblsz +
-                        (info->attr.mq_maxmsg * info->attr.mq_msgsize));
+                mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
+                                          info->attr.mq_msgsize);
 
                 spin_lock(&mq_lock);
                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
@@ -253,9 +353,9 @@ static void mqueue_evict_inode(struct inode *inode)
 {
         struct mqueue_inode_info *info;
         struct user_struct *user;
-        unsigned long mq_bytes;
-        int i;
+        unsigned long mq_bytes, mq_treesize;
         struct ipc_namespace *ipc_ns;
+        struct msg_msg *msg;
 
         clear_inode(inode);
 
@@ -265,17 +365,18 @@ static void mqueue_evict_inode(struct inode *inode)
         ipc_ns = get_ns_from_inode(inode);
         info = MQUEUE_I(inode);
         spin_lock(&info->lock);
-        for (i = 0; i < info->attr.mq_curmsgs; i++)
-                free_msg(info->messages[i]);
-        if (is_vmalloc_addr(info->messages))
-                vfree(info->messages);
-        else
-                kfree(info->messages);
+        while ((msg = msg_get(info)) != NULL)
+                free_msg(msg);
         spin_unlock(&info->lock);
 
         /* Total amount of bytes accounted for the mqueue */
-        mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
-            + info->attr.mq_msgsize);
+        mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
+                min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
+                sizeof(struct posix_msg_tree_node);
+
+        mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
+                                  info->attr.mq_msgsize);
+
         user = info->user;
         if (user) {
                 spin_lock(&mq_lock);
@@ -495,26 +596,6 @@ static struct ext_wait_queue *wq_get_first_waiter(
         return list_entry(ptr, struct ext_wait_queue, list);
 }
 
-/* Auxiliary functions to manipulate messages' list */
-static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
-{
-        int k;
-
-        k = info->attr.mq_curmsgs - 1;
-        while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
-                info->messages[k + 1] = info->messages[k];
-                k--;
-        }
-        info->attr.mq_curmsgs++;
-        info->qsize += ptr->m_ts;
-        info->messages[k + 1] = ptr;
-}
-
-static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
-{
-        info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
-        return info->messages[info->attr.mq_curmsgs];
-}
 
 static inline void set_cookie(struct sk_buff *skb, char code)
 {
@@ -848,7 +929,8 @@ static inline void pipelined_receive(struct mqueue_inode_info *info)
                 wake_up_interruptible(&info->wait_q);
                 return;
         }
-        msg_insert(sender->msg, info);
+        if (msg_insert(sender->msg, info))
+                return;
         list_del(&sender->list);
         sender->state = STATE_PENDING;
         wake_up_process(sender->task);
@@ -936,7 +1018,12 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
                         pipelined_send(info, msg_ptr, receiver);
                 } else {
                         /* adds message to the queue */
-                        msg_insert(msg_ptr, info);
+                        if (msg_insert(msg_ptr, info)) {
+                                free_msg(msg_ptr);
+                                ret = -ENOMEM;
+                                spin_unlock(&info->lock);
+                                goto out_fput;
+                        }
                         __do_notify(info);
                 }
                 inode->i_atime = inode->i_mtime = inode->i_ctime =